This invention relates to optical connectors and, more particularly, to optical plugs that include electrical connectors.
The growth in optical communications has been fueled by the extraordinary bandwidth that is available on optical fiber. Such bandwidth enables thousands of telephone conversations and television channels to be transmitted simultaneously over a hair-thin fiber that is made from a high-quality glass material. Nevertheless, bandwidth alone cannot satisfy some very simple needs that are easily handled by electrical cables. For example, electrical signals are the only practical way to interact with the existing communications infrastructure (e.g., standard telephone equipment) or even to operate a simple indicator lamp. And so it seems likely that the most desirable cables will combine electrical wires and optical fibers to enable designers to take maximum advantage of the strengths of each media. And while hybrid (i.e., electrical/optical) cables exist, hardware for connecting such cables to other communication equipment is presently too large, too costly or too cumbersome.
For example, patch panels are used to interconnect specific customers and equipment to other specific customers and equipment, and it is imperative that the interconnections be made accurately. One system is shown in U.S. Pat. No. 5,394,503, which discloses an optical fiber patch cable having end connectors that are arranged to operatively connect with patch panel couplings. Each patch cable includes one or more optical fibers and one or more electrical conductors. However, these end connectors and couplings are relatively bulky with large cross-section areas, each having many individual parts that do not yield to machine assembly. Consequently, they are neither space nor cost effective. Space is at a premium in such patch panels and an optical/electrical connector arrangement having a small footprint (i.e., cross-section area) is desirable, as is the ability to easily insert and remove closely spaced connectors in the patch panel.
Other hybrid connectors are known in the art and shown in: U.S. Pat. No. 5,109,452; U.S. Pat. No. 5,159,651; U.S. Pat. No. 5,473,715, and U.S. Pat. No. 5,745,622. However, none of these connectors provides the desired cost and space effectiveness. Some connectors have multiple latches while others require twisting, which means that additional separation between connectors is required so that an installer""s fingers can be positioned on both sides of the connector during installation and removal.
Another deficiency associated with many known plug connectors is that it takes too much effort to align the connector during installation because both electrical and optical connections need to be simultaneously engaged. This is the natural result of attempting to align a large number of connections at the same time.
Accordingly, what is desired is an optical/electrical plug connector that can be easily installed into a receptacle without significant alignment effort. Additionally, it is desirable that the optical/electrical plug connector have a relatively small cross-section area, a reduced number of parts, and the ability to easily install or remove from a densely packed patch panel.
The above-described deficiencies are overcome by an optical/electrical plug connector for terminating g optical and electrical transmission media. The plug connector includes a dielectric housing that encloses a fiber-holding apparatus, which supports an optical fiber that extends through a front opening in the housing. The plug connector further includes a back opening in the housing for receiving the optical fiber. A single cantilever latch is mounted on a top-side of the housing with its fixed end positioned toward the front opening and its free end extending toward the back opening. The latch is adapted to engage an associated receptacle in a locking relationship. A conductor-holding apparatus is positioned on a bottom side of the housing that is adapted to receive a number of insulated electrical conductors. The conductor-holding apparatus includes an equal number of metallic blade terminals that extend into the bottom side of the housing, pierce the insulation of the electrical conductors, and make electrical contact therewith.
In a preferred embodiment of the invention, the plug connector is designed to terminate one optical fiber and four insulated electrical conductors. Illustratively, the optical fiber may be glass or plastic. In the preferred embodiment, the optical fiber and the electrical conductors are contained within a single cable.
The optical/electrical plug connector of the present invention is suitable for high density panel mounting because the latch is positioned on the top side of the housing and the electrical connection apparatus is positioned on its bottom side. Such construction permits the left and right sides of the plug connector to be unencumbered by latching mechanisms. Indeed, because only minimum space is required on the lateral sides, jack structures having closely spaced (side-by-side) receptacles can be used in high-density applications.
Moreover, the plug connector of the present invention includes an optical plug portion that is designed to enter the associated jack receptacle before the electrical plug portion of the connector is engaged. In the preferred embodiment of the invention, the metallic blade terminals of the electrical plug portion are located at about the midpoint of the housing, although satisfactory alignment is achieved with only about twenty (20) percent of housing inserted in the jack receptacle before electrical contact is made. At this point, the optical plug portion of the connector is already providing meaningful assistance in the alignment of the electrical plug portion.